Cornell Feline Health Center
Cornell University College of Veterinary Medicine
Ithaca, New York 14853
October 17, 2001

In light of recent events, it is not surprising that concern is being expressed over the health risks the causative agent of anthrax, Bacillus anthracis, poses to cats. The Cornell Feline Health Center and the Veterinary Diagnostic Laboratory at Cornell University have received inquiries about the direct risk to cats, the potential role exposed or infected cats may play in transmitting infection to humans and to other animals, and methods to deal with exposed or infected cats.

It is important to note that no cases of illness or exposure to domestic cats have been identified in the recent anthrax incidents. Domestic cats would be unlikely primary targets, but it is conceivable that they could become infected from sources of the agent maliciously intended for human exposure. A cat with anthrax is incapable of transmitting the infection, but a cat's coat, once contaminated with anthrax spores, could in some cases pose a risk to health. For these reasons, it is important that companion animal veterinarians be informed about the disease, its effects on cats, its diagnosis, and its zoonotic potential.

How does anthrax affect cats?

Natural cases of anthrax in domestic cats are rarely reported. In contrast to herbivores, carnivores-including domestic cats-are relatively resistant to disease. In most reported cases, consumption of tissue from infected livestock was considered to be the likely source of infection. Because cats are efficient groomers, ingestion would be the expected route of exposure if their fur became contaminated with anthrax spores from a malicious attack. Clinical signs observed in the few reported feline cases included dyspnea and dysphagia resulting from swelling of the neck secondary to regional lymphadenopathy, hemorrhagic and ulcerative inflammation of the oral cavity and throat, enteritis, and enlargement of the kidneys, spleen, and liver. Sudden death with few premonitory signs has also been reported. The incubation period in naturally infected carnivores is often difficult to determine, but is believed to be approximately three to seven days with a range of one to 14 days.

When might I suspect that a cat has the disease?

Clinical signs associated with anthrax may provide clues, but they are signs common to other feline disorders. Sudden death in a cat without prior signs-although by no means unique to anthrax-might raise suspicion. The New York City Department of Health has compiled the following list of epidemiologic clues suggestive of a possible bioterrorist event:

Suspected or confirmed zoonotic diseases that are not endemic to the area, especially in the absence of recent travel history, or that have an unusual presentation

Simultaneous disease outbreaks in humans and animal populations

Any unusual temporal and/or geographic clustering of illness (e.g., pets from a given area, or that recently visited a particular park)

How do I confirm that anthrax is the cause of the disease?

Laboratory confirmation of disease is absolutely essential. The Veterinary Diagnostic Laboratory at Cornell University requests the following specimens from suspected cases (required supplies are available from the laboratory):

A pharyngeal swab submitted in Amies transport media (with or without charcoal)

1-2 ml of whole blood submitted in a blood culture bottle

1-2 ml of whole blood submitted in an EDTA (purple top) tube

Fresh specimens from infected cats are not infectious and pose no risk to human or animal health. However, once exposed to air, any vegetative forms of the organism present in the specimens will sporulate within several hours. Anthrax spores are the infectious form of the organism and are highly resistant to disinfection. Therefore, any inadvertent spills should be immediately cleaned and disinfected (disinfection instructions currently viewable in section II.1.b of the document, Basic Laboratory Protocols for the Presumptive Identification of Bacillus anthracis, from the Centers for Disease Control and Prevention. Do not open the body of a suspect anthrax case. Blood may be collected with a needle and syringe from the heart of a deceased patient. The body should be double bagged and frozen pending results of diagnostic tests.

Veterinary practices within the Cornell University College of Veterinary Medicine referral area should contact the Diagnostic Laboratory at (607) 253-3900 prior to sample submission. Specimens should be shipped overnight in a sealed, airtight, leak-proof container surrounded by absorbent material and placed inside a crush-proof mailer (mailing supplies are available from the Diagnostic Laboratory). Practices outside this referral area should contact their usual veterinary diagnostic laboratory prior to submitting samples.

If I'm presented with a cat with anthrax, at what risk are my staff, my clients, and I?

It is conceivable that you may be asked to examine or treat a cat with signs of disease consistent with anthrax. With the exercise of due caution, you should have no fear in doing so. Anthrax is not directly transmissible from animal to animal (e.g., cat to human or vice versa).

Will a cat with anthrax respond to treatment?

Attempts to treat cats with anthrax have never been documented. Extrapolating from treatment protocols for infected humans, administration of antimicrobials (e.g., enrofloxacin, doxycycline, or penicillin derivatives) for 6-8 weeks in addition to supportive measures would be a reasonable course of action. Prognosis is impossible to predict.

Whom should I notify if a patient has a confirmed anthrax infection?

Local public health officials should be notified immediately if anthrax is confirmed in a feline patient.

What if a cat presents with an unidentified powdery substance on its fur?

Rational thought should prevail! In the vast majority of cases, the powder will be a benign substance (e.g., dust from the environment, or flea powder applied to the cat unbeknownst to other family members). However, if after careful consideration, anthrax spores remain highly suspect, the following should be undertaken:

Call your local emergency response system (e.g., 911) or public health department; tests will be performed by appropriate public health officials

Avoid handling the cat more than is absolutely necessary; disposable gloves and garments should be used and subsequently destroyed in a manner determined by public health officials if anthrax exposure is confirmed

Confine the cat to one area to avoid spreading potentially infectious material

Disallow movement of people and materials into and out of the area of confinement

To avoid overwhelming the response system, use common sense in interpreting the situation. For example, cats covered with dust after rolling in the dirt should not be considered potentially exposed to a biological agent.

Where can I find additional information about anthrax?

The Cornell University Veterinary Diagnostic Laboratory webpage on emerging issues is an excellent source of information which includes links to other informative sites.